Li Xiao-Ping, Niu Jian-Lei, Gao Nai-Ping
1Department of Building Services Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
2Institute of Refrigeration and Thermal Engineering, School of Mechanical Engineering, Tongji University, Shanghai, 200092 China.
J Cent South Univ. 2012;19(3):645-650. doi: 10.1007/s11771-012-1051-0. Epub 2012 Mar 3.
Existed evidences show that airborne transmission of human respiratory droplets may be related with the spread of some infectious disease, such as severe acute respiratory syndrome (SARS) and H1N1 pandemic. Non-pharmaceutical approaches, including ventilation system and personal protection, are believed to have certain positive effects on the reduction of co-occupant's inhalation. This work then aims to numerically study the performances of mouth covering on co-occupant's exposure under mixing ventilation (MV), under-floor air distribution (UFAD) and displacement ventilation (DV) system, using drift-flux model. Desk partition, as one generally employed arrangement in plan office, is also investigated under MV. The dispersion of 1, 5 and 10 μm droplet residuals are numerically calculated and CO is used to represent tracer gas. The results show that using mouth covering by the infected person can reduce the co-occupant's inhalation greatly by interrupting direct spread of the expelled droplets, and best performance can be achieved under DV since the coughed air is mainly confined in the microenvironment of the infected person. The researches under MV show that the two interventions, mouth covering and desk partition, achieve almost the same inhalation for fine droplets while the inhalation of the co-occupant is lower when using mouth covering for large droplets.
现有证据表明，人类呼吸道飞沫的空气传播可能与某些传染病的传播有关，如严重急性呼吸综合征（SARS）和甲型H1N1流感大流行。包括通风系统和个人防护在内的非药物方法，被认为对减少同室人员的吸入有一定的积极作用。因此，这项工作旨在使用漂移通量模型，对混合通风（MV）、地板送风（UFAD）和置换通风（DV）系统下，戴口罩对同室人员暴露的影响进行数值研究。办公桌隔断作为办公平面中常用的一种布置方式，也在混合通风条件下进行了研究。数值计算了1、5和10μm液滴残余物的扩散情况，并使用一氧化碳来代表示踪气体。结果表明，感染者佩戴口罩可以通过阻断呼出飞沫的直接传播，大大减少同室人员的吸入量，在置换通风条件下效果最佳，因为咳出的空气主要局限于感染者的微环境中。混合通风条件下的研究表明，对于细颗粒飞沫，戴口罩和设置办公桌隔断这两种干预措施使同室人员的吸入量几乎相同，而对于大颗粒飞沫，戴口罩时同室人员的吸入量较低。
